Doctrine of Equivalents Is Strong Patentee Tool, but Needs Care

Todd Krause and Alyssa Monsen wrote an article entitled "Doctrine of Equivalents Is Strong Patentee Tool, but Needs Care" for Bloomberg Law, which discusses the doctrine of equivalents (DOE) as a means for patentees to assert infringement when claims are not literally infringed. The article reviews recent Federal Circuit and district court decisions, highlighting common pitfalls such as failing to tie DOE theories to specific claim limitations, providing insufficient evidence, and untimely assertion of DOE claims. It emphasizes the importance of particularized testimony, careful claim interpretation, and awareness of prosecution history estoppel and vitiation defenses. Ultimately, the authors advise that DOE remains a powerful tool when applied with precision and supported by robust evidence.

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